1. Field of the Invention
The present invention relates to an input device capable of generating, when an operating unit is rotated, a resistance torque in a direction opposite to an operating direction and a pull-in torque in the operating direction.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2005-507061 describes a brake including a magnetic-field responsive material. In the brake, a shaft is rotatably supported on a housing, and a rotor that rotates together with the shaft is provided in a first chamber of the housing. The magnetic-field responsive material and a magnetic-field generator are provided in the first chamber. The magnetic-field responsive material changes its fluidity depending on the intensity of a magnetic field. When no magnetic field is generated by the magnetic-field generator, the viscosity or shearing flow resistance of the magnetic-field responsive material decreases, and the shaft and the rotor may easily rotate. When a magnetic field is generated by the magnetic-field generator, the viscosity or shear flow resistance of the magnetic-field responsive material increases, and rotation of the shaft and the rotor is suppressed.
Japanese Unexamined Patent Application Publication No. 2003-50639 describes a manual input device. The manual input device includes an operating member, a carrier shaft that rotates together with the operating member, and an encoder provided on an output shaft of a motor. A carrier is fixed to the carrier shaft, and a plurality of planet gears are rotatably supported on the carrier. A sun gear is fixed to the output shaft of the motor, and the planet gears are engaged with peripheral portions of the sun gear. When the operating member is operated by hand so as to rotate and cause the encoder to operate, a rotational force in an operating direction or in a direction opposite to the operating direction is applied to the carrier shaft by the motor, and as a result, sensations of resistance and acceleration can be provided to a hand operating the operating member.
Although the brake described in Japanese Unexamined Patent Application Publication No. 2005-507061 can apply a braking force to the rotor through the action of the magnetic-field responsive material, the brake cannot apply a rotational force to the rotor, and thus, it is difficult to provide sensations of various operations to an operator.
The manual input device described in Japanese Unexamined Patent Application Publication No. 2003-50639 can provide sensations of resistance and acceleration to the hand operating the operating member by applying the power of the motor to the carrier shaft. However, in order to appropriately provide such sensations of resistance and acceleration to the hand, control of the motor becomes complex, and undesirable vibration may sometimes be generated by switching the direction of rotation of the motor. In order to cause the operating member not to move while being in a non-operating state, it is necessary to energize the motor even during the period when the manual input device is not in operation, which in turn results in an increase in power consumption.